docs: def convert_sshkey(cls, sshkey):
          """ Return dict param with valid entries for vm/paas methods. """
          params = {}
          if sshkey:
              params['keys'] = []
              for ssh in sshkey:
                  if os.path.exists(os.path.expanduser(ssh)):
                      if 'ssh_key' in params:
                          cls.echo("Can't have more than one sshkey file.")
                          continue
                      with open(ssh) as fdesc:
                          sshkey_ = fdesc.read()
                      if sshkey_:
                          params['ssh_key'] = sshkey_
                  else:
                      sshkey_id = Sshkey.usable_id(ssh)
                      if sshkey_id:
                          params['keys'].append(sshkey_id)
                      else:
                          cls.echo('This is not a ssh key %s' % ssh)
  
              if not params['keys']:
                  params.pop('keys')
  
          return params